This application claims the priority of German application 196 47 303.9, the disclosure of which is expressly incorporated by reference herein.
The invention relates to an independent wheel suspension for front wheels of a motor vehicle, having a wheel carrier which can be swivelled for steering purposes and whose first and lower joint is disposed on a semi-trailing arm and whose second joint situated above the horizontal wheel center plane is connected with a coupling rod which is supported on the semi-trailing arm in a hinged manner.
In the field of chassis construction, increasingly higher demands are made on the accident-caused, controllable deformability of the vehicle forward structure. Thus, it is attempted to design the side members of the vehicle such that they are upset or deformed as uniformly as possible in crash tests, among other situations. With respect to the construction of the front axle, this leads to the demand that the number of hinge points on the side member, which necessarily require a stiffening there, be minimized. As an alternative to the hinged connection to the side member, the hinge points of the control arms can be arranged on a cross member or the front wall of the passenger compartments, preferably in the area of the side members.
A front axle which, with the exception of the hinged connection of a hinged tie bar, meets this requirement is known from German Patent Document DE 26 42 939 C2. In the case of this space-saving independent wheel suspension, the wheel carrier and the coupling rod form a crank with an attached coupling hinge which crank stands on a semi-trailing arm and is swivellably disposed there about an approximately horizontal axis. On its upper joint, the wheel carrier is supported by way of an also approximately horizontally extending control arm on the wheel house or on a side member of the vehicle body. The control arm extends approximately at the level of the upper brake disk edge diagonally to the longitudinal axis of the vehicle. Because of the high control arm load during braking operations, the supporting points are particularly stiffened.
The invention is based on the need for an independent wheel suspension in which as few hinge points as possible are arranged on the side member and, in the case of a front-wall-side control arm support, relatively low forces have an effect in the hinge points situated there, if they are situated outside the side member hinging.
These and other needs have been met according to the present invention by providing an independent wheel suspension for a steerable front wheel of a motor vehicle, comprising a wheel carrier which is swivellable to steer said vehicle, said wheel carrier having a first and lower joint disposed on a semi-trailing arm and having a second joint connected with a coupling rod at a point above a horizontal center plane of the wheel, said coupling rod being hingedly supported on the semi-trailing arm, said wheel carrier including a lengthened portion extending upwardly at least to a level proximate a tread of a tire mounted on the wheel, an upper end of said lengthened portion being connected to a tie bar at an additional joint located on a line defined by said first and second joints, said tie bar being coupled to a front wall of the vehicle.
These and other needs have been met according to the present invention by providing an independent wheel suspension for a steerable front wheel of a motor vehicle, comprising a wheel carrier which is swivellable to steer said vehicle, said wheel carrier having a first and lower joint disposed on a semi-trailing arm and having a second joint connected with a coupling rod at a point above a horizontal center plane of the wheel, said coupling rod being hingedly supported on the semi-trailing arm at a hinge point, said coupling rod including a lengthened portion extending upwardly at least to a level proximate a tread of a tire mounted on the wheel, an upper end of said lengthened portion being connected to a tension strut at an additional joint located on a line defined by said hinge point and said second joint, said tension strut being coupled to a front wall of the vehicle.
These and other needs have been met according to the present invention by providing an independent wheel suspension for a steerable front wheel of a motor vehicle, comprising a wheel carrier which is swivellable to steer said vehicle, said wheel carrier having a first and lower joint disposed on a semi-trailing arm and having a second joint connected with a coupling rod at a point situated above a horizontal center plane of the wheel, said coupling rod being hingedly supported on the semi-trailing arm at a hinge point, an element of a spring strut supporting the wheel suspension being hingedly connected to the coupling rod at a point between the hinge point on the semi-trailing arm and the second joint, a lower end of the spring strut being supporting on the semi-trailing arm, an upper end of the spring strut being hingedly connected to a supporting wheel house or a front wall of the vehicle.
According to certain preferred embodiments, the coupling rod, which supports the wheel carrier on the semi-trailing arm, is lengthened upward at least into the close surroundings of the tire tread. At the end of the lengthened portion, a joint is situated on the imaginary lengthening of the section between the coupling rod hinged connection on the semi-trailing arm and the coupling rod hinged connection on the wheel carrier. On the joint, a tension bar is arranged which is supported on the vehicle front wall.
In addition, according to further preferred embodiments, the coupling rod is hinged between the hinged connection of the semi-trailing arm, which is forward when viewed in the driving direction, on the side member and the upper hinged connection on the wheel carrier in a hinged manner on an element of a spring strut supporting the wheel suspension on the vehicle body, the lower end of the spring strut being supported on the semi-trailing arm, but the upper end being fastened in a hinged manner on the supporting wheel house or the front wall.
In the first two variants, either the wheel carrier or the coupling rod is lengthened, for example, by one and a half to twice their length. As a result, the tension forces occurring in the hinged tie bar or the pull rod are reduced in comparison to the construction known from German Patent Document DE 26 42 939 C2 by approximately 33 to 50% while the angular conditions are approximately the same. A hinged connection to the vehicle front wall is therefore possible there without above-average reinforcements.
Together with the wheel carrier or the coupling rod, the lengthenings may, for example, be constructed as forged parts or sheet metal parts. Their respective design is determined, among other conditions, by stability requirements and space conditions.
The third variant will no longer require a hinged tie bar. The crank with the attached coupling hinge consisting of the coupling rod and the wheel carrier is supported on the spring strut of the front wheel suspension. This independent wheel suspension corresponds at least with respect to the spring strut to a McPherson front axle, but without the longitudinal rotation of the damper and the springing in the event of a steering angle.
Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of the invention when considered in conjunction with the accompanying drawings.